Cita APA (7th ed.)

ProQuest (Firm) & Polanka, S. (2011). No shelf required: E-books in libraries. American Library Association.

Cita Chicago (17th ed.)

ProQuest (Firm) i Sue Polanka. No Shelf Required: E-books in Libraries. Chicago: American Library Association, 2011.

Cita MLA (9th ed.)

ProQuest (Firm) i Sue Polanka. No Shelf Required: E-books in Libraries. American Library Association, 2011.